Justin Timberlake may be one of the biggest musicians in the world, but his 6-year-old son is unfazed by his fame. Jessica Biel hilariously shared what their eldest son thinks when he hears JT's music during Friday's .Jimmy Fallon first asked if Silas «freaks out» that Timberlake is in and Biel voices a character on her children's show, «Silas does definitely with Justin because of Branch,» Biel said of her husband's character in.